Cigarette with modified paper wrapper

ABSTRACT

An improved cigarette is prepared through use of modified cigarette paper as a wrapper. The wrapper is treated in preselected areas with a burn control additive comprising a mixture of potassium chlorate and sodium chlorate in a molar ratio of from 2.6:1 to 1.0:1. When the burning coal reaches the area of treatment, the treated area is burned away, allowing for the passage of air through the opening created during smoking of the cigarette. The mixture of potassium chlorate and sodium chlorate provides for a more stable treatment, particularly when the cigarettes having the thus treated wrapper are stored under conditions of high humidity.

United States Patent 1 Reynolds et al.

154] CIGARETTE WITH MODIFIED PAPER WRAPPER [75] Inventors: Martin Lance Reynolds, Anchorage,

Ky.; James R. Hammer-smith, Jeffersonville, Ind.; I-Iarlie A. Parish, Jr., Louisville, Ky.

[73] Assignee: Brown & Williamson Tobacco C0rporation, Louisville, Ky.

[22] Filed: Mar. 13, 1972 [21] Appl. No.: 234,210

UNITED STATES PATENTS 3,667,479 6/1972 Sanford ..l3l/9 X 3,473,535 10/1969 Stahly ..l3l/9 2,304,009 12/1942 Muth ...l3l/l5 B 2,836,183 5/1958 Fay et al..... ..l3l/4R 2,992,647 7/1961 Figge ..131/l5 B X 1 Mar. 27, 1973 FOREIGN PATENTS OR APPLICATIONS 320,013 1/1970 Switzerland ..l31/l5 B OTHER PUBLICATIONS N. I. Sax, (Text) Dangerous Properties of Industrial Materials, Reinhold Publishing, N.Y. 3rd ed. pgs. 484, 961, 1,000, 1,101 cited (1968).

Primary Examiner-Robert W. Michell Assistant ExaminerGeorge M. Yahwak AttorneyDavid S. Kane et al.

57 1 ABSTRACT An improved cigarette is prepared through use of modified cigarette paper as a wrapper. The wrapper is treated in preselected areas with a burn control additive comprising a mixture of potassium chlorate and sodium chlorate in a molar ratio of from 2.6:1 to 1.0:1. When the burning coal reaches the area of treatment, the treated area is burned away, allowing for the passage of air through the opening created during smoking of the cigarette. The mixture of potassium chlorate and sodium chlorate provides for a more stable treatment, particularly when the cigarettes having the thus treated wrapper are stored under conditions of high humidity.

3 Claims, 1 Drawing Figure I ll/ CIGARETTE WITH MODIFIED PAPER WRAPPER CROSS-REFERENCES TO RELATED APPLICATIONS This application is related to copending application Ser. No. 3,862, now US. Pat. No. 3,667,479, of Robert Sanford, Robert Johnson, and Thomas Summers entitled Cigarette with Modified Paper Wrapper," filed Jan. 19, 1970 and to application Ser. No. 885,615, now abandoned, of Ivor Hughes and Sydney Green for Smoking Articles, filed Dec. 16, 1969, both assigned to the same assignee as the present application.

BACKGROUND OF THE INVENTION The previously referenced applications, particularly Ser. No. 3,862, now US. Pat. No. 3,667,479, Sanford et al., disclose and claim a cigarette wrapper modified by the application of a burn control additive. The burn control additive is selected from the group consisting of sodium chlorate, potassium chlorate, alkali and alkaline earth metal perchlorate, sodium bromate, sodium nitrite and potassium nitrite, along with nitric acid. These additives are applied in preselected areas of the wrapper and cause that portion of the wrapper to burn more rapidly than the adjoining, untreated portions of the wrapper, as the burning coal approaches. By the described treatment, the constituent delivery, including the delivery of total particulate matter and carbon monoxide is significantly reduced. Further, constituent delivery is leveled over the length of the cigarette, so that the delivery from each puff is essentially the same as from any other pufi.

While the treatment referred to is entirely adequate and provides the results described, a problem may be encountered when cigarettes having modified wrappers according to the previously described invention are stored under conditions of high humidity. Under such conditions, cigarettes treated, particularly, with sodium chlorate may become less effective. The loss in effect is due to migration of the sodium chlorate treating agent as influenced by the absorption of ambient moisture. Under severe conditions, the sodium chlorate applied in the preselected areas may migrate in such a way that the preselected areas are blurred, or are lost entirely.

SUMMARY OF THE INVENTION In accordance with the present invention it has been discovered that a proper combination of potassium chlorate and sodium chlorate, in a critical ratio, will provide a cigarette having the benefits described in the previously referenced application and the additional benefit of being highly storage stable, even under ambient conditions of very high humidity. It has been discovered that this critical ratio requires that the potassium chlorate and sodium chlorate be applied in a molar ratio of between 26:1 and 1.0:]. Such a ratio provides for proper stability and adequate advance removal of the wrapper in the treated areas.

Another important factor is that sufficient chlorate anion be present so that the treated portion of the paper is adequately burned away in advance of the burning coal. It has been found that the level of chlorate anion should be at least 0.80 milligrams per square centimeter in the areas which are treated.

Because of the low solubility at room temperature of potassium chlorate, it is necessary that, in the preferred manner of application, the solution of potassium chlorate and sodium chlorate be applied at an elevated temperature. Preferably, this temperature is in the range of from about to 100C, most preferably from to C. If desired, various materials may be added to this solution to increase the viscosity and provide additional aid in the printing of distinct patterns.

BRIEF DESCRIPTION OF THE DRAWING The drawing illustrates one form of pattern employable with the combined burn accelerating agent of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The accompanying drawing illustrates one pattern which may be employed using the combination burn accelerating agent according to the present invention. A wrapping 10, suitable for use on a cigarette, is illustrated. The tip or mouthpiece end is designated 11. Printed, or otherwise applied to the wrapping, is the combination burn accelerating agent according to the present invention in a plurality of squares 12a through l2j. It will be noted that the squares 12a, closest to the mouthpiece end, are larger than the squares l2j, furthest from the mouthpiece end, and that the size of the squares progressively diminishes from 12a through 12j. All of the squares within a given row, e.g., 12a, 12e, are of the same size. The purpose of increasing the square size, as the mouthpiece is approached, is to provide additional air dilution to the smoke in this region as more fully explained in the aforementioned copending application Ser. No. 3,862, now US. Pat. No.

3,667,497. Of course, it will be recognized, that not only the pattern shown in the accompanying figure, but any of the patterns shown in the just referenced copending application can be employed. 4

The important feature, according to the present invention, is the application of the coating with a combination of potassium chlorate and sodium chlorate. In order to assure sufficient chlorate anion to provide for opening of the printed areas in advance of the burning coal, there should be at least 0.80 milligrams per square centimeter of chlorate anion in the particular treated areas, i.e., 12a through l2j. The total application of chlorate is limited only by the saturation of the paper with the treating solution in the treated areas. Generally, however, no more than 1.0 milligram per square centimeter of chlorate anion is applied.

Of further importance, and critical to the present invention, is the ratio of potassium chlorate and sodium chlorate employed. The ratio, on a molar basis, should be between 2.621 and 1.0:] of potassium chlorate to sodium chlorate. This mixture assures the stability of the product, even under high ambient humidity conditions, but also assures a regular burning of the treated area with a sharp pattern.

The most advantageous way of applying the mixture of potassium chlorate and sodium chlorate is from a gravure roll etched to provide the desired pattern, such as the pattern of the accompanying figure, employing a water solution. However, as potassium chlorate has a low solubility at room temperature, the solution must be heated to maintain the potassium chlorate in solution. The temperature of the solution should be maintained at about 85 to 100C, preferably from about 90 to 95C.

The amounts of potassium chlorate and sodium chlorate in the solution are limited, not only by the solubility, but also by the necessity of obtaining the desired ratios and the desired amounts of chlorate anion on the cigarette wrapper treated. Thus, the amounts of potassium chlorate should be in the range of from 27 to 19 grams per hundred grams of solution and the sodium chlorate in the range of from 9 to 14 grams per hundred grams of solution.

In addition to the required potassium and sodium chlorates, the solution may also contain other materials, particularly viscosifiers. The viscosifiers aid in obtaining good appearance of the printing, particularly by a sharply defined print pattern. They accomplish this by reducing the lateral migration of the sodium chlorate. Of course, this also reduces the penetration, but it has been found that amounts of viscosifiers of up to about 0.5 percent reduce the lateral migration without adversely affecting penetration. Preferred viscosifiers have been found to be locust bean gum and food grade xanthan gum.

The total area which should be covered with the mixed chlorates is from about 3.0 to 4 square centimeters, regardless of the pattern of application. Generally, the covered area is from about 3.3 to 3.5 square centimeters for king size cigarettes and from about 3.6 to 3.8 square centimeters for 100 mm. cigarettes. A particularly advantageous way of accomplishing this total area of coverage for the 75 mm. of paper used on a 100 mm. cigarette (25 mm. filter), is as shown in the accompanying figures where the lengths of the sides of the squares are as follows:

12a 3.0 millimeters 12b 2.95 millimeters 12c 2.9 millimeters 12d-- 2.85 millimeters l2e 2.8 millimeters l2f- 2.75 millimeters 12g 2.7 millimeters 12h 2.65 millimeters 12i- 2.5 millimeters l2j- 2.0 millimeters With five squares on each line, this is a total area of about 3.7 square centimeters. The total amount of chlorate anion applied in this area should vary from about 2.8 to 3.8 milligrams, and preferably 3.0 to 3.4 milligrams. Thus, the amount of chlorate anion per square centimeter ranges from about 0.7 milligrams per square centimer to 1.3 milligrams per square centimeter.

In order that those skilled in the art may better appreciate the results achieved according to the present invention, the examples below are given. These should be considered as illustrative only and not as limiting in any way the full scope of the invention as covered in the appended claims. In each example where smoke delivery is measured, both the cigarettes according to the present invention and the control cigarettes were smoked on smoking machines commonly employed in the art as, for example, the Phipps and Bird smoking machine. In each-case, the smoking machine took a puff of 35 ml. volume over a period of two seconds, with one puff each minute.

EXAMPLE 1 An aqueous solution was formed with 26 parts by weight potassium chlorate, 9 parts by weight sodium chlorate, and 65 parts by weight water. The solution was maintained at 95C. and was applied to a king size cigarette wrapping in a pattern similar to that indicated in the accompanying figure by gravure printing. The treated area was 3.4 square centimeters. Those portions of the wrapper which were treated contained 0.8 milligrams per square centimeter of chlorate anion and the ratio of potassium cation to sodium cation was 2.3:1. Standard cigarettes were formed in the manual cigarette forming machine marketed under the trademark LAREDO and, upon smoking, were found to give a tar delivery 30 percent less than that of control cigarettes made in the same way, but with untreated wrapping paper.

EXAMPLE 2 An aqueous solution was formed containing 20 parts by weight potassium chlorate and 14 parts by weight sodium chlorate in 66 parts water maintained at a temperature of 95C. This was applied to cigarette wrapping paper by gravure printing, as in Example 1. The treated area of the paper contained 0.9 milligrams per square centimeter of chlorate anion and had a potassium cation to sodium cation mole ratio of 1.2:1. Cigarettes were formed and tested in the same manner as in Example 1 and showed a tar delivery 29 percent less than that of control cigarettes. The delivery of total particulate matter was essentially uniform over the length of the cigarette on a per puff basis.

EXAMPLE 3 As previously indicated the primary object of the present invention is to provide cigarettes which will perform in the desired manner even though stored under ambient conditions of high humidity. Accordingly, cigarette wrappers were printed with a variety of solutions to provide varying potassium to sodium ratios. One group of these cigarettes was smoked immediately for a determination of total particulate matter delivery, while another group was sealed in jars at F. for a period of six weeks, after which they were tested to determine tar deliveries. The

results are given below in Table 1:

only

It can be seen that the cigarette treated with only sodium chlorate shows a significant increase in the amount of tar delivery when stored at high temperature for a sustained period. On the other hand, samples 2 and 3, formed according to the present invention, show essentially no change in total particulate matter delivery on such storage. While a cigarette treated with only potassium chlorate actually showed a reduction in total particulate matter delivery after storage as described, the pattern of burn-out, as the burning coal approached the treated areas, was very uneven and both the aesthetic effect and the leveling of constituent delivery per puff were significantly diminished.

In accordance with the present invention, a treatment for modification of a cigarette wrapper has been disclosed where the treatment is stable under conditions of high temperature and high humidity. Even after storage under such adverse conditions, the so treated cigarettes are capable of providing a significantly reduced total particulate matter delivery when compared with control cigarettes. In addition, the delivery of total particulate matter is essentially constant, on a per puff basis, over the length of the cigarette.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In a cigarette having a tobacco rod surrounded by a uniform, imperforate paper wrapper, the improvement which comprises modification of the wrapper by treatment of said wrapper in a plurality of specific, separated areas, with a strong, combustion supporting, oxidizing agent, where the amount of said oxidizing agent closest to the butt end of the cigarette is greatest, the improvement which comprises a mixture of potassium chlorate and sodium chlorate in a molar ratio of 2.6:l to l.0:l as the combustion supporting, oxidizing agent.

2. The cigarette of claim 1 wherein the amount of chlorate anion present is from 0.7 to 1.3 milligram per square centimeter in those areas in which it is applied.

3. The cigarette of claim 1 wherein the area treated is from 3 to 4 square centimeters. 

2. The cigarette of claim 1 wherein the amount of chlorate anion present is from 0.7 to 1.3 milligram per square centimeter in those areas in which it is applied.
 3. The cigarette of claim 1 wherein the area treated is from 3 to 4 square centimeters. 